If you want to use the parameter "-Template" you probably cannot use the parameter "-MemoryGB" ...

Check this by running "Get-Help New-VM" then check in which of the 4 (I think it's four, it used to be :) ) New-VM sections, the parameter "-Template" can be found and make sure all your other parameters are in there.

You'll probably need to set your memory/cpu parameters after the VM is created.

Try this: there is no parameter with GB but MB
secondly, diskmb should be a numeric value you gave array as the value?
#-----------------------------------
$dsc=Get-Datastore DC1_A_T1_SRM_PL006
$tmp=Get-Template -name *win*2008*r2*ent
$name= "DEV-SQL-DBA-01"